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Finger Sticking Techniques

(This article appeared in the Voice of the Diabetic, Volume 16, Number 2, Spring 2001 Edition, published by the Diabetes Action Network of the National Federation of the Blind. Updated July 2004)

We know blood glucose monitoring is important because it helps us keep our diabetes under control. You should test often. How you test matters too, as poor technique wastes strips and can give you inaccurate readings. Good testing techniques will also minimize the number of times we must stick our fingers. If you have not achieved good finger-sticking techniques, I recommend the old adage, Practice makes perfect.

I am a type 1 diabetic, and I empathize with individuals whose fingertips are bruised and sore from testing, and with others who have trouble getting enough blood from the puncture site. Test strips are extremely expensive, and it is frustrating for people who must stick themselves over and over while trying to get enough blood for a good reading.

Finger Sticking Locations

You should generally use the sides of your fingers for sticking sites. More nerves are present in the center of fingers, so lancing in this location may bring more pain. Note several glucose monitors now allow "alternative site" testing - but their instructions specify that critical readings should be taken frm the fingers.

I use all ten fingers for blood sugar testing, and on each finger I have four penetration sites. Some people occasionally use the middle of a finger if the sides have become too sore.

Ann S. Williams, MSN, RN, CDE, herself a type 2 diabetic, chooses her test sites by day of the week and time of day. Her left index finger is for Monday, left middle finger for Tuesday, left ring finger for Wednesday, etc. On each finger, the side toward the thumb, opposite the base of the fingernail is for suppertime, and the same side, opposite the middle of the fingernail, is for bedtime. Any extra tests are done in the area around the top of the fingernail.

She writes: "By using this method, you end up lancing the same site only once a week. I like doing it this way because I have such a hard time remembering where I last lanced, and this way I can figure out where I am supposed to be by day of the week and time of day."

Cleaning Fingertips

If possible, wash your hands with warm, soapy water, which will, besides cleaning, bring additional blood to the fingers. Rubbing alcohol can of course be used; but alcohol may cause fingers to become dry, which might cause more pain when lancing. The fingers should be totally dry before testing.

Ronald James, MD, has had type 1 diabetes for 51 years. This diabetologist says, "If your finger is dry and clean, I see no reason you have to use rubbing alcohol."

Note: Using a good skin cream may help soften your fingertips, and will help with appearance. Apply it after you test.

Blood Clotting

If the stick location doesn't clot thoroughly, you may experience bruising and soreness. After putting blood on the test strip, you should use a tissue and apply firm pressure directly on the puncture site. Some diabetics will thoroughly clot after a few seconds, while others may take longer. Once the bleeding stops, you should again use a tissue and apply firm pressure directly over the puncture location. If blood is on the tissue, you know bleeding is still occurring under the skin. So firm pressure is needed a bit longer.

Once a diabetic (blind or sighted) regularly tests his or her blood glucose, they will know roughly how long they take to clot. Also, if blood is seeping from the puncture spot, it can usually be felt because it is sticky. If you are not sure if the blood has thoroughly clotted, you need only to apply firm pressure a short while longer.

Getting Enough Blood

When lancing, you should strive for a sample just big enough, just enough blood to make your meter work, thus minimizing pain and bruising. Be aware different meters require different blood sample amounts--and newer meters are less "thirsty" than their ancestors. If you are a good bleeder, there should be no problem; but if not, and if you are sure you are using the strip correctly--that the blood is going on the right place--try altering the procedure. Instead of gently milking the lanced finger, you may need to vigorously milk. By "milking the finger," I mean stroking and pulling downward, from the base of the finger toward the tip and the sample site.

One class of people, those suffering from edema (excess fluid in the tissues) needs to be cautious with vigorous finger-milking. As kidney problems are one cause of edema, check with your doctor about this condition.

I have talked to many diabetics who have trouble getting enough blood after the finger stick. If there is not enough blood on the test strip, the test result could be skewed. I have experimented several times, by very gently milking blood from my punctured finger, and within two to three minutes I pricked another finger and vigorously milked the sample site. Guess what? In every test there was no appreciable difference in sample results.

The rubber band method may be helpful too. Wrapping a doubled rubber band between the first and second joint of the finger to be lanced will cause the finger to become engorged with blood. This will help a larger drop of blood to form. Hold the rubber band down with the thumb while lancing. Remove the band as soon as lancing is completed.

Many diabetics have for a long time vigorously milked their fingers to get an adequate blood sample. The clinical difference between gentle milking and vigorous milking is not significantly different. The result in all likelihood will not be significant enough to alter any insulin dosage. Again, we should try to get an adequate blood sample by very gently milking the puncture site.

Many lancing devices allow you to adjust the depth of penetration. Shallow penetration should minimize any pain. The same thing can usually be accomplished by holding the lancet more lightly against the skin. Use the shallowest penetration that provides you enough blood for the test.

In the mailbox section of Diabetes Forecast, December 1998, Adam Bloom, MD, discussed obtaining blood samples by milking the fingers, and that the NCCLS, the National Committee for Clinical Laboratory Standards, states one can enhance blood flow from the puncture "by holding the puncture site downwards and gently applying continuous pressure...proximal to the puncture site," but that (states the NCCLS) "Strong repetitive pressure (milking) should not be applied; it may cause...contamination of the specimen with tissue fluid."

Although such "zero-error" considerations are important for the research scientist in his/her laboratory, in practice, however, this mixing of tissue fluids with blood does not appear to affect the readings obtained on home blood glucose meters significantly enough to be of concern. "I know of no studies that have been done specifically to prove this point (states Dr. Bloom), but I do know from experimenting with my own meter that the readings I obtain when I milk, even vigorously, are not meaningfully different."

Remember that even if you use perfect testing technique, a glucose meter will most likely not give you the same results twice in a row.

Wiping Blood Off After Lancing

Many diabetics do not wipe off the first drop of blood after lancing. Years ago, the health community recommended the first drop of blood should be discarded, because it was believed impurities or contamination from rubbing alcohol could affect the test. If your hands are clean, there is no reason to remove the first drop, and if you use rubbing alcohol, there is still no good reason to remove the first drop of blood, because the difference between sample results is insignificant. Many health care teams who deal with diabetes do not wipe off the first sample, but some do. As I said earlier, if alcohol is used, you need to be sure the site is absolutely dry before lancing.

Ronald James, MD, says, "I think if your finger is clean, you don't need to wipe the first drop off."

Note also that folks who find it difficult to get enough blood for the test will find it that much harder if they wipe away the first drop!

Lancing Devices

Find which lancing device makes finger sticking least painful for you. I like the Softclix made by Roche Diagnostics, but there are many others on the market. Bloodborne diseases can be transmitted by fingerstick, so never use someone else's lancet. Be aware lancet points dull fairly rapidly, and if you re-use, things can get painful, and you may not get enough blood. Lancets are cheap; change them often.

Health care practitioners should show patients how to properly test for blood glucose, because many have not mastered correct testing technique. My physician asks all diabetic patients if his staff can show them proper blood glucose testing techniques, which include finger sticking.

There is one lancing device that does not require lancets. The Lasette Plus, from Cell Robotics, is a laser lancet. It burns a small, clean hole sufficient for a blood test. The company says there is no pain. This device costs $495. For information contact: Cell Robotics, Inc., 2715 Broadbent Pkwy. NE, Suite A, Albuquerque, NM 87107; telephone: 1-800-846-0590.

Another alternative is the AscensiaMicrolet Vaculance, from Bayer, an unusual combination of lancing device and small pump. Designed to obtain blood samples from sites other than the fingers, it is not meant for finger use. The device costs $25, and is available from Bayer Corporation; telephone: 1-800-348-8100; Web site http://www.glucometerdex.com/.

Good finger sticking techniques are an important aspect of diabetes self-management. Blood glucose testing should be made as simple as possible because far more patients will test, and test more often--and regular, frequent testing is critical to good diabetes management.